Makefile separates file names and suffixes

Reference resources Get filename without extension within makefile - Stack Overflowhttps://stackoverflow.com/questions/13995906/get-filename-without-extension-within-makefile And GNU make 8.3 Functions for File Nameshttps://www.gnu.org/software/make/manual/make.html#File-Name-Functions The minimum example is as follows ：

SRCNAME = $(basename bar_1.foo.c)
SRCTYPE = $(suffix bar_1.foo.c)

The result is SRCNAME yes  bar_1.foo,SRCTYPE yes .c（ Note that the suffix here contains periods ）.

Practical examples are as follows ：

SRCNAME = $(basename $(SRC))
SRCTYPE = $(suffix $(SRC))
all:
ifeq ($(SRCTYPE),.s)
all: assembly
else ifeq ($(SRCTYPE),.c)
all: program
else
	$(error Source file suffix must be *.c or *.s)
endif

assembly:
	@echo ASM
program:
	@echo C

Notice the second and third here all target Do not add indents ,  Reference resources conditional - How do you conditionally call a target based on a target variable (Makefile)? - Stack Overflow

Be careful ifeq No space can be added before or after the comma of the condition , Add only one at the end endif.

For example, if you execute

make SRC=rv32_fib.s

Will output

ASM